Conventionally, as a sealing material used for assembly of various kinds of electronic material modules, there has been proposed a resin composition comprising an ethylene-based copolymer as a base material and an organic peroxide as a crosslinking agent (Patent Literature 1).
In addition, there has been proposed an adhesive sheet for a solar cell which is constituted of 100 parts by weight of an ethylene-based copolymer and 0.05 to 0.5 part by weight of an organic peroxide, and comprises a multifunctional monomer having four or more acryloyl and/or methacryloyl groups in total (Patent Literature 2).
Further, there has been proposed a sealing film for a solar cell which comprises an ethylene-unsaturated ester copolymer, a crosslinking agent and a crosslinking aid, in which the crosslinking aid comprises a polyfunctional (meth)acrylate of a polyhydric alcohol and TAIC (Patent Literature 3).
Meanwhile, in the sealing material using an ethylene copolymer as a resin, particularly, insulation properties (volume resistivity value) thereof come into question. In this point of view, the above conventional proposals are not necessarily sufficient.